The term “second screen” commonly refers to the use of a personal electronic device, such as a tablet computer or smartphone, to enhance the experience of a person viewing content on another device, referred to in this context as the “first screen.” (A second-screen device is sometimes referred to as a “companion device,” and software applications supporting second-screen functionality may be referred to as “companion apps.”) A second screen of this sort may include features that enable the viewer to interact with the content shown in the first screen, such as television shows, movies, music, or video games. For this purpose, the information displayed on the second screen is typically synchronized with the content being transmitted to the first screen.